Taperssection.com

Gear / Technical Help => Ask The Tapers => Topic started by: morst on January 20, 2026, 11:20:46 PM

Title: seeking suggestions to process old audience DAT with asymmetric waveform
Post by: morst on January 20, 2026, 11:20:46 PM

I think the show was too loud for the lavaliere mics. (AudioTechnica ATM35s pair > Sony TCD-D10 Pro II > DAT @48kHz)


Any suggestions for processing this so i can get a little more level out of it?


It's not really a DC offset issue.


Would phase rotation help even it out?


Thanks in advance.
I don't wanna work too hard on it as it sounds ok as-is, but i'd like to make it a little closer to 0dBFS, so it plays back louder.

Title: Re: seeking suggestions to process old audience DAT with asymmetric waveform
Post by: EnglishSkylarking on January 21, 2026, 05:01:33 AM

I agree with your general assessment since the peaks are asymmetrical for the music and appear more equal in the quieter portions. To me the later half looks worse or like it might have something else going on, but it could end up being nothing.

If that were my tape then I'd run it through iZotope's phase rotation as a first step to see how it looks and then listen for any negative impacts.

Title: Re: seeking suggestions to process old audience DAT with asymmetric waveform
Post by: Gutbucket on January 21, 2026, 01:17:59 PM

Looks like what I've occasionally seen through unbalanced single-ended preamps / recorders.  Sometimes when mics or other circuits are near overload, or when a battery is weak.. basically the same thing I suppose.  Although some waveforms tend to be naturally somewhat asymmetrical at times, like with trumpets.

Might play around with phase rotation. But I suspect that phase rotation of L vs R won't do what you want since both L and R visually appear to have the same asymmetry.  However, some FM radio broadcasters manipulate phase of the difference channel as a way of reducing crest factor so as to achieve increased RMS values through the transmitter without increased peak values.  With that in mind, maybe view the waveforms as Sum/Difference rather than L/R and look to see if the asymmetry predominates one channel more than the other.  If it does, phase rotation of one channel (sum or difference) with respect to the other may achieve what you want.

I wonder if there are any plugin tools specifically designed to manipulate one side of a waveform to better match (or intentionally mismatch) the other?  In this case, making the compressed looking positive going side match or at least more closely follow the negative going side.  Shouldn't be difficult to do digitally, and would make for a useful if rather esoteric digital tool.

Title: Re: seeking suggestions to process old audience DAT with asymmetric waveform
Post by: EmRR on January 21, 2026, 05:47:37 PM

Quote from: Gutbucket on January 21, 2026, 01:17:59 PM

Looks like what I've occasionally seen through unbalanced single-ended preamps / recorders.  Sometimes when mics or other circuits are near overload, or when a battery is weak.. basically the same thing I suppose.  Although some waveforms tend to be naturally somewhat asymmetrical at times, like with trumpets.

Might play around with phase rotation.

Yep.  Phase rotation can surely get it more symmetrical, question is whether it sounds right for vocals and transient impact. 

Title: WAS seeking suggestions to process old audience DAT with asymmetric waveform
Post by: morst on January 21, 2026, 08:01:17 PM

Thanks for weighing in everyone.
I've decided to leave the bits alone, and whoever would like to experiment with them can do so any time.

I'll post shortly and link here and in kickdown.

(https://preview.redd.it/qs3j0vrrmyx41.jpg?width=640&crop=smart&auto=webp&s=4bde97038a3c518bd30d340b1ae8b49cc630fc73)
edit:
link is here
https://archive.org/details/JustinHinds2000-05-28 (https://archive.org/details/JustinHinds2000-05-28)